In a number of sports such as tennis, racquetball, squash, badminton, or the like, a type of sports racket is used which relies upon a strong rigid frame having a plurality of tensioned strings forming a net-like pattern across the frame center opening. An elongated handle extends from the frame to be gripped by the player. While the structures of such sports rackets vary substantially, several features are common to them all. For example, the strength of the frame and handle and balance of the racket is often critical to optimum performance in the particular sport in which it is used. In addition, substantial effort is devoted to maintaining appropriate tension within the string array to assure the desired resilience and impact characteristics of the racket.
It is a characteristic of such sports rackets that optimum striking power and energy application to the game object or ball is attained by impacting the racket within a relatively small portion of the string arrangement. Such portion is often referred to as the "sweet spot" of the racket. Thus, substantially less energy is imparted to the ball or game object outside the sweet spot. However, striking the ball or game object in such areas may nonetheless suffice in game play even though not optimum. Unfortunately, however, the presence of the supporting frame often limits the available hitting area of the string arrangement due to the radius of curvature or size of the object being struck. In particular, game or ball objects being struck partially by the outer frame at the extremes of the string arrangement results in poor play and unpredictable rebound direction and, as a result, low control capability by the player. While all such sports activities using such sports rackets suffer from this problem in some degree, tennis is probably the most critical due to the larger ball used. The greater diameter of the tennis ball requires that the ball must be struck a substantial distance in from the outer frame to avoid impact between the ball and frame.
Recognizing the problems such as those described above inherent in the design and fabrication of such sports rackets, practitioners in the art have provided a virtually endless variety of sports rackets designs. Some sport racket designs have provided rackets which are in essence "two-sided" having dual string arrays on each outer edge of the racket frame. Others have provided various improvements in frame design and materials while still others have endeavored to improve string arrangement and tensioning. For example, U.S. Pat. No. 5,197,731 issued to Svoma, et al. sets forth a STRING SUSPENSION AND FRAME CONSTRUCTION FOR SPORTS RACKETS having a stringed playing surface wherein selected ends of individual string segments meet the frame alternately in front or behind the plane of the playing surface.
U.S. Pat. No. 5,184,818 issued to Lo sets forth a METAL RACKET having a hollow looped head portion defining a cross-section lying on a plane perpendicular to a string web held by the looped head portion. The cross-section includes a convex outer periphery with two terminating ends disposed on opposite sides of the stringed web.
U.S. Pat. No. 5,172,911 issued to Chang sets forth a METAL RACKET FRAME having a metal tube which is bent so as to form a curved head portion. The racket frame further includes a converging throat portion which extends from the head portion together with a handle portion which extends from the throat portion. The metal tube is provided with a pair of spaced elongated partitions which extend along the length of the metal tube. The partitions confine a central space therebetween and a side space on each side of the center space.
U.S. Pat. No. 4,561,655 issued to Mortvedt sets forth a TUBULAR STEEL RACKET FRAME HAVING VARYING CROSS-SECTION which provides strength in the lower racket portion to reduce the torsional and flexing movements of the frame in the area of the lower portion.
U.S. Pat. No. 4,279,418 issued to Lacoste sets forth RACKETS FOR TENNIS AND OTHER GAMES having a oval or pear-shaped stringing surface on an auxiliary element for maintaining the strings in a median plane at determined places in which at least some strings are wound simultaneously around the frame and around the auxiliary element.
U.S. Pat. No. 4,204,690 issued to Blackburne sets forth RACKETS having double stringing disposed in two generally parallel planes located on the opposite edges of the head frame.
U.S. Pat. No. 4,141,549 issued to Hayes, et al. sets forth a TENNIS RACKET having a frame member forming a head portion having duplicate strung ball striking matrices. Each matrix is substantially coplanar with a respective front and rear face of the frame member.
U.S. Pat. No. 4,049,269 issued to Blackburne sets forth RACKETS including a handle intended to be held in the hand and carrying a head having an open marginal frame defining a central opening across which extends tension stringing carried by the head frame. Instead of being located in a single plane disposed centrally of the bounded head frame, the stringing of the racket is disposed in two generally parallel planes located on opposite sides of the frame.
U.S. Pat. No. 3,968,966 issued to D'Aquanni sets forth a RACKET WITH TWO INDEPENDENTLY STRUNG FACES in which a racket frame supports two string matrices parallel to each outer edge of the racket frame.
U.S. Pat. No. 3,904,202 issued to DeLorean sets forth a RACKET including a string tensioning system symmetrically disposed about the racket frame so as to impose substantially equal spring tension forces throughout the length of the frame.
U.S. Pat. No. 3,899,172 issued to Vaughn, et al. sets forth a TENNIS RACKET HAVING IMPROVED STRENGTH FACTOR utilizing a novel frame strip, plastic throat piece structure, grommet means and handle structure to provide an improved racket having improved strength characteristics as well as reliability and durability.
U.S. Pat. No. 3,752,478 issued to Flak sets forth a RACKET FRAME formed of extruded aluminum provided with a tri-hollow cross-section enabling the frame to be reduced in weight without detracting from the strength of the frame.
U.S. Pat. No. 1,502,845 issued to Blache sets forth a RACKET having plural grooves in the outer racket frame which receive and guide the racket strings.
French Patent 1,212,195 sets forth a sports racket having a generally rectangular cross-section frame defining outer surface grooves which receive and guide racket strings.
British Patent 2,007,985 sets forth a sports racket having tensioned strings wound thereon. The frame includes an inwardly projecting rigid lip contacting one side of the strings and operative to change the effective length of the string depending upon the direction from which the string array is struck.
French Patent 855,902 sets forth a resiliently strung sports racket having helically wound string patterns.
British Patent 409,924 sets forth an improved sports racket having a frame defining a plurality of apertures therethrough which receive the tensioned string and secure it to the frame.
While the foregoing described prior art devices have in some instances enjoyed commercial success and have to some extent improved the art generally, there remains nonetheless a continuing need in the art for a sports racket which more effectively addresses the above-described problems while remaining relatively simple in construction.